Progress bars

In order that viewers do not get lost, and following Dennis’ advices (thank for the idea! 🙂 ), qualitative progress bars have been added. Aside from a lack of documentation, the volumetric renderer seems to be mature enough for an inclusion in an official blender release (stability, rational UI, flexibility..caution: these are not Ton’s words, only strong assumptions based on objective facts!). Please notice that these bars only deal with blender, so even if there’s already a Navier-Stokes simulator for realistic Smoke/fire, it’s nonetheless in the TODO state (Daniel?) because it’s not integrated inside blender. For volumetric optimizations, adaptative step size still has to be implemented (in progress because first builds had this feature so the code is available, but the new, more robust renderer is implemented in a way which causes its addition less straightforward) . For external shadows, the proposal has been postponed in order to design (= in agreement with Broken/Ton) a more general system, which can deal with buffered shadows instead of raytraced ones only. Photon Mapping is a joint project with Matt Ebb, so work will be resumed as soon as he will have a stable core to share with, avoiding thus rewrites. In the meantime, writing an unbiased renderer allows better understanding of the fundamental algorithms (see last posts for more reasons) and also will allow to have a tool for calibration inside blender.

As previously said, do not fear dilution of the work because we have to wait for the volumetric inclusion in a next blender version before doing more radical changes caused by optimization/better integrations. (see last posts). In the mean time, keep learning the existing features (cf. download the manual) whose interface won’t change for an official release and do VFX experiments by using the particle system.

p.s: remember, volumetrics uses the raytracer which is cpu-intensive, so if you use it in a scene, DO use layer rendering: render only the smoke/clouds with ray activated, then the rest of the scene without it, then composite all the layers through blender powerful nodal system. For shadows from the volumetrics, you can fake it through dummy objects whose shape/alpha cast shadows similar to the volumetrics ones…

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12 thoughts on “Progress bars”

I love your projects 🙂
But if you are looking for something to be improved in blender while waiting for the volumetrics integration, why not have a go on blenders video sequenzer. There is no good video editing software for Linux. Only with blender it is possible to do some more advanced stuff like video compositing but still the video sequenzer in blender is very limited.

Excuse my dumbness but is the Navier-Stokes simulator going to be an option in the particle physics panel? Wouldnt that make it easier to visualize the effect without having to rerender everytime you make a change? And also it can take advantege of other particle tools like baking and such.

Your question is not dumb at all (smart instead):
Navier-Stokes is a grid-based simulation, like the current fluid simulator in blender, while the particle system is grid-free. This make the vizualisation(through isosurfaces) less straigforward.
For your proposal, an additional function must be coded to convert the grid-value into curves value that the particles can follow.
In physical terms, grid-based simulation are called “Eulerian”, while simulation where we follow a particle along its trajectory is called “Lagrangian”. Farsthary is familiar with both approach, and used a hybrid one (Semi-lagrangian) because some physical phenomena are more intuitive to represent in a model than another.
Clearly, the lagrangian approach is very elegant because we don’t have to define a domaine, instead a particles number (ex: you can water flowing from a tap all over your scene) and also for integration with the particle system (initial position and particules speed suffice). However, as the physical equations for fluids are naturally expressed with the Eulerian approach, changing the reference and keeping efficiency is not easy at all (many paper about this)

.. So to conclude, I think that it will be coded first like the current fluid simulator, independantly from the particle system..
Anyway, this kind of project need a lot of coding power: Farsthary is too isolated (very specific coding requiring very good communication with experienced blender coder) to do this alone in the coming year

Genscher showed interest in implementing the simulator, but ofcourse he didnt commit himself to it yet.
perhaps farsthary and/or broken could have a work with him about it.
having viewport visualisation of the simulation is kinda a must.. having to guess what it’ll look like and waste time rendering is just not really an option in the long run.

I like the idea of not using a domain for simulation and I think that it would be great if the particle system in the future could have more physics alternatives like fluid,smoke,fire and gas. To me it feels simpler than having to create a domain and run a simulation. Instead you could do a simulation directly from the particle panel with low number of particles and directly see the result while later increase the number for a full simulation.